1. Field of the Invention
The present invention relates to blends of acrylonitrile/butadiene/styrene copolymers (ABS) with certain copolyesters. These blends have been found to have an unexpectedly good balance of physical properties.
2. Discussion of the Background
Art of interest in connection with this invention includes U.S. Pat. No. 3,644,574, which discloses blends of poly(tetramethylene terephthalate) with polystyrene or with copolymers having a styrene content greater than 50%.
U.S. Pat. No. 3,564,077 discloses that the impact properties of poly(ethylene terephthalate) can be moderately improved by blending the poly(ethylene terephthalate) with small amounts, generally less than 10% by weight of a styrene-butadiene copolymer.
U.S. Pat. No. 4,117,034 discloses that the addition of certain graft polymers to amorphous aromatic polyesters of aliphatic diols provides an improvement in the impact strength characteristics and a concomitant reduction in the notch sensitivity of the composition. The polyesters disclosed by U.S. Pat. No. 4,117,034 can be amorphous polyesters derived from aromatic dicarboxylic acids and aliphatic diols, e.g., the phthalate copolyesters of aliphatic diols having three or more carbon atoms, such as copoly(1,4-cyclohexalene dimethylene iso/terephthalate) and the like.
U.S. Pat. No. 4,096,202 discloses that impact modifiers for poly(alkylene terephthalates) based on rubbers of polybutadiene, butadiene-styrene copolymers, butadiene-acrylonitrile copolymers, ethylene-propylene rubbers, polyisobutene and polyisoprene have been suggested, making reference to U.S. Pat. No. 3,919,353.
U.S. Pat. No. 4,496,202 also discloses blends of about 99% to 60% by weight of a poly(alkylene terephthalate) and about 1% to 40% by weight of a multi-phase composite interpolymer. The multi-phase composite interpolymer is made up of about 25 to 95 weight % of a first elastomeric phase polymerized from a monomer system, and about 75% to 5% by weight of a final, rigid thermoplastic phase form of epoxy groups polymerized in the presence of the elastomeric phase. The monomer system is made up of about 75% to 99.8% by weight of a C.sub.1-6 alkyl acrylate, 0.1% to 5% by weight of a crosslinking monomer, and 0.1% to 5% by weight of a graft linking monomer. This blend is said to provide an impact modified poly(alkylene terephthalate) without significantly increasing melt viscosity.
DE No. 33 32 325 discloses blends of acrylonitrile/butadiene/styrene copolymers with polycarbonate. JP No. 53-71155 discloses three component blends of aromatic polyesters, acrylonitrile/butadiene/styrene copolymers and polycarbonate.
The present invention provides blends of ABS copolymers with certain copolyesters which possess a high notched Izod impact strength combined with a good balance of other properties, i.e., flexural modulus, tensile properties, heat deflection temperature, and hardness. These blends are useful in making automotive and appliance components.